Method of natural gas evacuation from subject to repair area of main gas pipeline

The research was performed in order to obtain the physical picture of the movement of condensed droplets and solid particles in the flow of natural gas in elbows and T-junctions of the linear part of the main gas pipeline. 3D modeling of the elbow and T-junction was performed in the linear part of the gas main, in particular, in places where a complex movement of multiphase flows occurs and changes its direction. In these places also occur swirls, collisions of discrete phases in the pipeline wall, and erosive wear of the pipe wall. Based on Lagrangian approach (Discrete Phase Model – DPM), methods of computer modeling were developed to simulate multiphase flow movement in the elbow and T-junction of the linear part of the gas main using software package ANSYS Fluent R17.0 Academic. The mathematical model is based on solving the Navier–Stokes equations, and the equations of continuity and discrete phase movement closed with Launder–Sharma (k–e) two-parameter turbulence model with appropriate initial and boundary conditions. In T-junction, we simulated gas movement in the run-pipe, and the passage of the part of flow into the branch. The simulation results were visualized in postprocessor ANSYS Fluent R17.0 Academic and ANSYS CFD-Post R17.0 Academic by building trajectories of the motion of condensed droplets and solid particles in the elbow and T-junction of the linear part of the gas main in the flow of natural gas. The trajectories were painted in colors that match the velocity and diameter of droplets and particles according to the scale of values. After studying the trajectories of discrete phases, the locations of their heavy collision with the pipeline walls were found, as well as the places of turbulence of condensed droplets and solid particles. The velocity of liquid and solid particles was determined, and the impact angles, diameters of condensed droplets and solid particles in the place of collision were found. Such results provide possibilities for a full and comprehensive investigation of erosive wear of the elbow and T-junction of the linear part of the gas main and adjacent sections of the pipeline, and for the assessment of their strength and residual life.

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REGULATORY PROVISION OF SAFETY OF GAS TRANSPORT. CONSTRUKTIONAL DESIGN OF MOBILE COMPRESSOR STATIONS

Ukrainian Journal of Civil Engineering and Architecture ◽

10.30838/j.bpsacea.2312.270421.13.746 ◽

2021 ◽

pp. 13-19

Author(s):

V. BIELIKOV ◽

Z. MATSUK

Keyword(s):

Natural Gas ◽

Gas Pressure ◽

Gas Pipeline ◽

Industrial Safety ◽

Technical Requirements ◽

The World ◽

Transportation Process ◽

Mobile Compressor ◽

Main Gas Pipeline ◽

Gas Supply

Problem statement. The basis for the safety and efficiency of the main gas transportation in the world is the tightness of the gas transportation system. A component of the level of industrial safety and efficiency of gas transmission enterprises is the emissions of natural gas into the working area, the environment and the associated costs. Numerous methods of repairing pipeline gas transportation facilities, such as enhancing the bearing capacity of pipelines, repairing defects under gas pressure without interrupting the transportation process, etc., are either not devoid of risks from the point of view of industrial safety, or are energy and resource inefficient. The main type of repair that restores the operable state of the gas transmission system is the replacement of defective equipment, but it is still associated with the release of large volumes of natural gas into the environment. In the second decade of the 2000s, thanks to the rapid development of compressor technology and the invention of a sufficient number of ways to connect compressor units (stations) to main gas pipelines, without stopping the gas transportation process, gas transmission enterprises of the world had a real opportunity to evacuate gas from pipeline sections subject to repair (maintenance ) or accumulate it (control gas pressure in local areas), but the analysis of world experience in the development of gas pressure control technology in localized sections of gas pipelines allows us to assert that there are certain disparities between them in terms of operational safety and the complete absence of regulatory support for the transportation process in Ukraine gas using mobile compressor stations. With this approach to the production process, it is difficult to improve the safety and efficiency of the gas transportation process. The potential for reducing natural gas emissions from the world's gas industry reaches billions of cubic meters of natural gas per year. Purpose of the article. Development of technical requirements for mobile compressor units (stations), which will make it possible to design domestic gas compressor units (stations) capable of safely performing work on pumping natural gas from a localized section of the main gas pipeline to an existing main gas pipeline, within no more than 96 hours, without restrictions on gas supply to consumers. Conclusion. The technical requirements developed by us for mobile compressor units (stations) allow us to design domestic compressor units (stations) capable of safely performing work on pumping natural gas from a localized section of the main gas pipeline to the existing main gas pipeline, within no more than 96 hours, without restrictions on gas supply to consumers.

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Regularities of safe control of piston compressor units of mobile compressor stations

Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu ◽

10.33271/nvngu/2021-2/076 ◽

2021 ◽

pp. 76-81

Author(s):

Z.N Matsuk ◽

T.V Bunko ◽

A.S Belikov ◽

V.A Shalomov

Keyword(s):

Natural Gas ◽

Gas Pressure ◽

Gas Pipeline ◽

Relative Mass ◽

Time Interval ◽

Relative Pressure ◽

Gas Pipelines ◽

Mobile Compressor ◽

Gas Pumping ◽

Main Gas Pipeline

Purpose. Ensuring the optimal mode of gas transportation from local sections of the main gas trunkline (GT), subject to repair (maintenance) and/or shutdown, to existing main gas trunkline based on the calculation, determination, and establishment of rational values of the operating modes of mobile compressor stations during the entire time of gas pumping. Methodology. The studies are based on existing physical principles and laws that describe the effect of the properties of natural gas and the geometric parameters of pipelines through which gas is pumped on the dynamics of changes in the mass and pressure of the transported gas. The calculation of the change in the mass and pressure of the gas in the gas pipeline from which the gas is pumped is based on a number of existing theoretical and empirical dependencies included in the generally accepted methods for their calculation. Known physical relationships and mathematical models are used to carry out the calculations. Findings. The mass approach to the issue of calculating the gas transportation time is more mathematically accurate than the volumetric one. The ratio of the relative mass to the relative gas pressure in a localized section of the main gas pipeline, during the entire pumping time, is a constant value. The use of the values of the quantities obtained at the point of intersection of the graphs of changes in the relative mass and relative pressure of the gas, in the preliminary calculation of the time for pumping gas, or pressure, or mass, or the volume of gas in each time interval, makes it possible to select the optimal rate of building up/reducing gas pressure by compressor units and optimal modes of gas transportation by operating gas pipelines during the operation of mobile compressor stations. Originality. The proposed approach to calculating and determining the time of gas pumping by mobile compressor stations from local sections of the main gas pipelines subject to repair (maintenance) and/or shutdown to sections of existing main gas pipelines proves that it is advisable to establish stable patterns in the transportation of natural gas using reciprocating compressor units only after modeling in time the change in the mass and pressure of gas in the local section of the main gas pipeline from which the gas is pumped. Practical value. The proposed approach to optimizing the time of gas pumping by mobile compressor stations makes it possible to increase the level of energy and resource efficiency of gas transmission enterprises, as well as to improve the technical and economic indicators of technologies for repairing the main gas pipelines, compressor stations of main gas pipelines associated with the need to bleed gas from sections of the main (technological) pipelines subject to repair (maintenance) and/or shutdown. Optimization of gas pumping time significantly reduces the time spent by employees of gas transmission enterprises under the influence of hazardous and harmful production factors, thereby reducing the level of relevant risks. Gas emissions and associated risks are reduced by 90%.

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